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Prove the following identities, where the angles involved are acute angles for which the expressions are defined: sinθ-2sin3θ2cos3θ-cosθ=tanθ

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प्रश्न

Prove the following identities, where the angles involved are acute angles for which the expressions are defined:

`(sin theta-2sin^3theta)/(2cos^3theta -costheta) = tan theta`

Prove that `(sin theta-2sin^3theta)/(2cos^3theta -costheta) = tan theta`

योग
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उत्तर

L.H.S = `(sin theta-2sin^3theta)/(2cos^3theta -costheta)`

= `(sintheta(1-2sin^2theta))/(costheta(2cos^2theta-1))`

= `(sinthetaxx(1-2sin^2theta))/(costhetaxx{2(1-sin^2theta)-1})`

= `(sin thetaxx(1-2sin^2theta))/(costhetaxx(1-2sin^2theta))`

= `tantheta` 

= R.H.S

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अध्याय 8: Introduction to Trigonometry - EXERCISE 8.3 [पृष्ठ १३१]

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एनसीईआरटी Mathematics [English] Class 10
अध्याय 8 Introduction to Trigonometry
EXERCISE 8.3 | Q 4. (vii) | पृष्ठ १३१

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